Method of balancing current volume based on temperature setting for an electrode-type liquid heater for a boiler

ABSTRACT

An electrode surge tank system of heating fluid (water) in a boiler or tank in which there is a central inverted nonconductive heat generating chamber with an open bottom positioned at the top of the boiler. A plurality of spaced electrodes protrude downward into said heat generating chamber so that the electrodes will be immersed to a maximum degree when the boiler or tank is filled. A circulating pipe connects the top of the inverted chamber with the lower portion of the tank or boiler to convey heated vapor (steam) to the lower portion of the tank or boiler to thus heat the boiler fluid. A modulating valve is provided in the circulating pipe line to control the flow of heated vapor (steam) and thus control the heat input. The closing of the modulating valve (by a temperature responsive element) also provents the escape of vapor from the top of the inverted heat generating chamber and produces a buildup of vapor pressure therein which in turn forces the fluid level therein to drop. The lowering of the fluid level in the inverted chamber (surge tank) reduces the degree of submergence of the electrodes and thus the degree of generation of heat and when the electrodes are no longer submerged the heat generation stops. As the fluid temperature in the boiler drops, the vapor pressure above the fluid also drops allowing the fluid level to rise and the cycle of fluid he ting continues. Thus a desired fluid temperature may be maintained. To prevent a full electric surge load when starting, there is provided an auxilliary air pressure system connected to the surge chamber so that with a control valve the air pressure may be transferred into the upper portion of the surge chamber, thus forcing the level of the fluid therein to drop and reducing the degree of submergence of the electrodes to any desired degree to thus reduce the power demand when starting its heat generating cycle.

United States Patent [1 1 Zeitlin et al.

[ 1 Oct. 23, I973 METHOD OF BALANCING CURRENT VOLUME BASED ON TEMPERATURE SETTING FOR AN ELECTRODE-TYPE LIQUID HEATER FOR A BOILER Inventors: Edward J. Zeitlin, Purdys; Lee

Leighton, Mohegan Lake, both of NY.

Assignee: Edward ,I. Zeitlin, Purdys, N.Y.

Filed: Aug. 30, 1971 Appl. No.: 175,816

Saunders 219/284 Primary Examiner-A. Bartis Attorney-Howard T. Jeandron [57] ABSTRACT An electrode surge tank system of heating fluid (water) in a boiler or tank in which there is a central inverted non-conductive heat generating chamber with an open bottom positioned at the top of the boiler. A plurality of spaced electrodes protrude downward into said heat generating chamber so that the electrodes will be immersed to a maximum degree when the boiler or tank is filled. A circulating pipe connects the top of the inverted chamber with the lower portion of the tank or boiler to convey heated vapor (steam) to the lower portion of the tank or boiler to thus heat the boiler fluid. A modulating valve is provided in the circulating pipe line to control the flow of heated vapor (steam) and thus control the heat input. The closing of the modulating valve (by a temperature responsive element) also provents the escape of vapor from the top of the inverted heat generating chamber and produces a buildup of vapor pressure therein which in turn forces the fluid level therein to drop. The lowering of the fluid level in the inverted chamber (surge tank) reduces the degree of submergence of the electrodes and thus the degree of generation of heat and when the electrodes are no longer submerged the heat generation stops. As the fluid temperature in the boiler drops, the vapor pressure above the fluid also drops allowing the fluid level to rise and the cycle of fluid he ting continues. Thus a desired fluid temperature may be maintained. To prevent a full electric surge load when starting, there is provided an auxilliary air pressure system connected to the surge chamber so that with a control valve the air pressure may be transferred into the upper portion of the surge chamber, thus forcing the level of the fluid therein to drop and reducing the degree of submergence of the electrodes to any desired degree to thus reduce the power demand when starting its heat generating cycle.

1 Claim, 5 Drawing Figures 1 METHOD OF BALANCING CURRENT VOLUME BASED ON TEMPERATURE SETTING FOR AN ELECTRODE-TYPE LIQUID HEATER FOR A BOILER This invention relates to an electrode surge tank system of electric heating of a fluid in a boiler or tank by the immersion of the electrodes in the fluid of the surge tank and a means to modulate the level of the fluid and thus change the degree of current flow through the water or fluid within the surge tank caused by the changing area of submergance of the electrodes and thus the resistance across the submerged area of the electrodes to produce heat and raise the temperature of the water or fluid contained in the boiler.

It is an object of this invention to provide an electrode surge tank system of heating of a fluid in a boiler or tank in which there is a heat generating section in which electrodes are immersed in the fluid and the fluid is heated by current flowing between electrodes, thus heating the conducting fluid in the heat generating section and producing a vapor pressure within the surge tank and controlling this pressure to change the level of the fluid in the surge tank and in turn the degree of heat generated.

It is a further object of this invention to provide a system of electric heating of a fluid in a boiler or tank in which the heat generating section is a central inverted chamber extending downward from the upper plate of said boiler or tank and in which electrodes are provided to extend downward into said central inverted heat generating chamber When the boiler or tank is filled with a fluid, the electrodes are deeply immersed in said fluid and the fluid is heated by current flowing through the fluid from one electrode to another, thus by conduction and circulation heating all the fluid within the boiler or tank. The water within the central inverted chamber provides the heat generating means and because it is heated first and is hotter than the surrounding boiler water vapor will be produced in the central inverted chamber. If the vapor is allowed to escape and circulate back into the boiler, the fluid level in the central chamber and the boiler remains constant. Ifa modulating valve is introduced to control the escape and flow back of the vapor, the level of the fluid in the central heat generating chamber may be lowered by the increase in vapor pressure and the fluid level in the surge tank or boiler will drop. This lowering of the fluid level in the central chamber decreases the degree of immersion of the electrodes and thus the degree of electrode surface for heat conversion.

It is a further object of this invention to provide a pressure sensor for the central surge chamber of the boiler to thus determine the varying size of the orifice in a modulating valve and to thus provide a controlled release of the vapor pressure within the central chamber. The orifice is restricted to cause the rise in pressure. The water level in the control chamber is lowered by the vapor pressure within the central chamber, when a desired pressure is obtained within the central chamher.

With the rise in pressure the fluid level in the surge tank will in turn drop thus changing the degree of exposure of the electrodes to the fluid and in turn the degree of heat conversion. Secondly the modulating valve may produce a balance where the generation of vapor by the degree of electrode immersion produces a vapor that increases in pressure when restricted to thus maintain a desired fluid level. The desired fluid level will maintain a heat conversion as chosen and determined by the setting of the desired temperature to control said modulating valve.

It is a further object of this invention to provide an improved electrode immersion type tank or boiler for heating fluid in which the tank or boiler is provided with a-central heat generating section and an outer fluid surge absorbing section and in which the fluid level in the heat generating section can be raised or lowered to various fluid levels manually or automatically to correspond to desired temperature setting for the fluid to be heated.

It is a further object of this invention to provide a sight gauge connected to the central chamber to show the degree of heat conversion in the central chamber from maximum when the fluid is at its highest level to minimum when the fluid is at its lowest level.

It is a further object of this invention to provide a controlled auxiliary air pressure that may be connected to the upper portion of said central chamber to provide an auxiliary pressure to force the fluid level down below the electrodes and shut off current flow and prevent an excessive current overload when starting the heating cycle, instead the fluid is gradually allowed to rise to start a minimum current flow for the start of a controlled cycle of heat conversion.

It is a further object of this invention to provide a fluid having the optimum electrical resistivity for a system of immersion type electric heating of the fluid contained in a vessel.

It is a further object of this invention to provide an immersion type heater comprised of separated electrodes mounted in the upper and plate or section above the fluid in the boiler or tank and in which each electrode is electrically insulated to prevent conduction from one electrode to the other and from the boiler shell.

Other objects of this invention shall be apparent by reference to the accompanying detailed description and the drawings in which FIG. 1 is a partial cross section of a boiler with a central chamber and immersion type electrodes,

FIG. 2 is a cross section similar to FIG. 1 showing the variation in fluid level when at an increased temperature,

FIG. 3 is a schematic illustration partially in cross section of a boiler and auxiliary equipment,

FIG. 4 is a plan view taken on line 4-4 of FIG. 1, and

FIG. 5 is a cross sectional view (slightly enlarged) taken on line 55 of FIG. 4. v

Referring to the drawing s and particularly FIGS. 1 and 2, there is illustrated a portion of a boiler 10 positioned in an upright vertical position with an upper end plate 11 mounted and sealed to the boiler walls 10A. Plate 11 supports in a hanging position an elongated vertically positioned ceramic central chamber 12 by means of brackets 11 Chamber 12 is non-conductive. In addition, a circular plate 12A of ceramic is supported on top of chamber 12 as an insulating barrier for a plurality of electrodes 15 that are inserted through plate 11 and extend to approximately the lower end of central chamber 12. Each electrode is mounted through plate 11 and insulated from the conductive plate 11 by means of a ceramic non-conductive sleeve 15A (FIG. 5). Each electrode 15 extending through the non-conductive sleeve A. To prevent any water or steam leakage around the electrodes 15, there are provided seals S, and S at either end of sleeve 15A. The sleeve 15A is mounted through an aperture in plate 1] and similarly to prevent leakage, there are provided seals S and 8,, one located on each side of plate 11. To retain seals 8;, and S, the sleeve 15A is threaded at its upper end while having an enlarged base B. A nut 17 is threadably secured to sleeve 15A at the top end and it will compress seals S and 8, when it is secured to hold sleeve 15A as shown. The electrode 15 passes through sleeve 15A and is formed in two parts threadably connected, 151.. being the lower section and 15U the upper section. When the ISU section is secured, the seals S and S: will be compressed to provide the necessary seal around each electrode. The electrodes are thus completely sealed to prevent fluid leakage and thoroughly insulated to prevent current leakage. The boiler 10 in use will be filled with a fluid to a prescribed level 16 (FIG. 1). When the fluid is at this level the fluid is cold, has not been heated. When current is applied to the electrodes, that is, when current flows, in F IG. 2, from one electrode to another electrode through the water or fluid surrounding the, electrodes, there is a resistance set up in'the fluid or water producing heat. Thus when the electrodes are energized, FIG. 1, the fluid within chamber 12 will be heated to the point that it begins to form vapor, the vapor being sealed between plate 11 and the level of the fluid, as vapor is formed and the pressure grows, the pressure will lower the fluid level down to a point as illustrated in FIG. 2 and as the fluid drops from the level in FIG. 1 to the level in FIG. 2, there is necessarily a decrease of the area of the electrodes exposed to the fluid and therefore the degree of heat produced for heating the fluid. Thus with control, the level of the fluid within chamber 12 will drop as vapor or steam pressure increased. To control the heating of the water in the boiler, a vapor outlet 18 (FIG. 3) passes or is connected to a control valve V. Valve V in turn being connected to an inlet 19 to boiler 10. When valve V is open the hot vapor will simply circulate through 18 past valve V and return to the boiler through inlet 19 to heat the water. when valve V is closed the vapor or steam pressure within chamber 12 will build up and the level of the'fluid will be forced downward. To establish a control, either a temperature responsive element 20 or a pressure responsive element 20A may be used. With element 20, when the water in the boiler is below the temperature setting of 20, the steam or vapor from chamber 12 will pass freely through 18 and through control valve V and back to the boiler through return inlet 19 to heat the water in the boiler 10. When the temperature of the water reaches a predetermined setting, the element 20 will close a circuit to the motor of valve V and the motor will be energized to modulate valve V. With valve V so operated to restrict the flow of vapor, the vapor or steam pressure will build up in chamber 12 (FIG. 2) and since it can not escape, the fluid level will be forced downward and it may reach a point C (FIG. 2) at which less steam is produced (less immersion of the electrodes) and as the water in the boiler tends to cool, the element 20 will respond demanding more heat and opening valve V to permit circulation of vapor back to the boiler. Thus a selected temperature on element 20 will provide a control of the heating induced into the fliud. Of course all during this operation water in the boiler is being heated. It is therefore apparent that the degree of immersion of the electrodes regulates the degree of resistance to current flow and therefore the degree of heat transfer. The boiler may have alternative controls being provided with a thermostat 20 as described or it may be provided with a pressure switch 20A to permit setting a desired steam or vapor pressure for the fluid being heated. The water is heated by current flowing between the electrodes, thus heating the fluid within the boiler. The water within the central chamberbeing hotter than the water in the boiler, vapor will be formed in the upper portion of the inner chamber. When the vapor is allowed to flow back to the boiler, the water level within the chamber remains constant. By means of a control valve V (controlled by a pressure sensor 20A which is affected by vapor pressure, the level of the water in the central chamber is controlled. As the pressure rises, the aperture of the valve V is restricted, as a result the water level in the central chamber drops thus exposing less of the electrodes to the water and less heat conversion and less vapor pressure and so the water level on the control chamber will-drop until a balanced relation between heat conversion and degree of electrode immersion is reached and the valve V will open. The valve opening and closing to maintained a desired setting. The setting of the pressure sensor is based upon calibrated pressure produced by the immersed electrodes at the varying levels of immersion.

Certain refinements may contribute to the operation of this type of fluid heater. For example outlet 18 is connected to a two way valve 27. Valve 27 in one position connects outlet 18 to valve V and the return inlet 19, in the other position outlet 18 is connected to valve 29 and the air line 28. Line 28 is connected to an air pressure source 40. The air pressure may be used as a means of supplying air pressure to the central chamber 12 to force the fluid level down to a minimum contact with the electrodes 15. Thus at a start of the heating cycle, there will be a minimum current demand. The level of the fluid being lowered by air pressure will be indicated in the sight gauge 24. In addition an air bleed valve 30 (FIG. 1) may be connected to the central chamber. Bleed valve 30 may be proviced with an adjustable orifice thus any level from minimum upward may be set as desired and theheat conversion is automatically set by the degree of fluid coverage of the electrodes. After a minimum heating cycle at the start and a gradual rise of temperature, the two way valve 27 may be reset to allow the vapor under pressure to flow into the line to valve V and automatic operation based on a pressure setting of the pressure responsive element 20A may be resumed. If the water supply in the auxiliary tank is not up to temperature setting desired, the pressure responsive sensor 20A may be set at a low pressure and the fluid level in the surge chamber 12 will rise and thus produce a greater degree of heat conversion. The auxiliary tank 108 is heated by a coil 36 from boiler 10 thus bringing tank 10B up to the same temperature as boiler 10. Fresh fluid may be supplied through valve 21 to maintain the desired fluid level in boilder 10. Also fluid may be drained or bled from boiler 10 by opening valve 26. The fresh fluid entering tank 10 is forced upward by a baffle 23, while fluid being drained is from the bottom of tank 10 by means of valve 26. The pressure switch 20A may be located anywhere at the top of the boiler, however it is shown in the line from outlet 18. Sensors Switch A responds to the vapor pressure to provide a means of the opening or closing valve V as desired. The electrodes 15 whether a pair or a plurality as illustrated in FIG. 4 may be mounted individually in a good sealed relationship. Thus the electrodes may be easily removed for inspection. The sight gauge or water column 24 may be connected to the bleed line adjacent valve 26 to provide a visual gauge. A further refinement is the provision of a ceramic non-conducting central chamber which is provided to act as a barrier for current flow to thus prevent current leakage to the shell of the boiler.

Although we have shown a particualr form of boiler and a particular form of inner chamber, the shape of the boiler and the shape of the inner chamber may vary without departing from the spirit of this invention and although we have shown a pair of electrodes and a plurality of electrodes in certain configuration, the positioning of the electrodes may vary without departing from the spirit of this invention.

The invention described in detail in the foregoing specification is subject to changes and modifications without departing fr om the principle and spirit thereof. The terminology used is for purposes of description and not of limitation; the scope of the invention being defined in the claims.

What is claimed is:

1. In an electrode liquid heater comprising, a boiler containing a conductive liquid to be heated, a central inverted non-conductive chamber having an open bottom and closed top and positioned at the top end of said boiler and enclosing a plurality of electrodes suspended from the top and extending down into said chamber so that they will be immersed when said boiler is filled with a liquid, said electrodes spaced apart and connected to a power line, said electrodes providing a means to produce heat and vapor in said chamber by causing a current flow through said liquid, an auxiliary air pressure system connected to the upper portion of the central inverted chamber, said system being comprised of a tank of air under pressure connected to a check valve and in turn to the upper portion of said inverted chamber, and said inverted chamber connected to a bleed valve for bleeding air pressure from said chamber, a rotary motor driven modulating vale with a variable orifice communicating on the one side to the upper portion of said central chamber and communicating on the opposite side to the boiler to provide the means to convey the heated vapor through the boiler to heat the liquid when the modulating valve is open and providing the means to shut off the flow of vapor and produce a build-up of vapor pressure in said central chamber forcing said liquid level to be lowered when the modulating valve is closed, a sensor that responds to the fluid pressure created by the heating of the water in said central chamber of said boiler to operate the moudlating valve to in turn control the rise and fall of the liquid level in said central chamber and establish a desired liquid level of electrode immersion to produce a desired heat conversion to the liquid. 

1. In an electrode liquid heater comprising, a boiler containing a conductive liquid to be heated, a central inverted nonconductive chamber having an open bottom and closed top and positioned at the top end of said boiler and enclosing a plurality of electrodes suspended from the top and extending down into said chamber so that they will be immersed when said boiler is filled with a liquid, said electrodes spaced apart and connected to a power line, said electrodes providing a means to produce heat and vapor in said chamber by causing a current flow through said liquid, an auxiliary air pressure system connected to the upper portion of the central inverted chamber, said system being comprised of a tank of air under pressure connected to a check valve and in turn to the upper portion of said inverted chamber, and said inverted chamber connected to a bleed valve for bleeding air pressure from said chamber, a rotary motor driven modulating valve with a variable orifice communicating on the one side to the upper portion of said central chamber and communicating on the opposite side to the boiler to provide the means to convey the heated vapor through the boiler to heat the liquid when the modulating valve is open and providing the means to shut off the flow of vapor and produce a build-up of vapor pressure in said central chamber forcing said liquid level to be lowered when the modulating valve is closed, a sensor that responds to the fluid pressure created by the heating of the water in said central chamber of said boiler to operate the modulating valve to in turn control the rise and fall of the liquid level in said central chamber and establish a desired liquid level of electrode immersion to produce a desired heat conversion to the liquid. 